Influence of the magnetic core on efficiency of the gauss gun

The following calculations were executed when I was projecting a multistage ball-firing coilgun, and trying to utilize a magnetic core in its construction. Slightly modified script http://coilgun.ucoz.ru/FEMM_calc/Stator/gauss_ver_2_5.lua for SCR-driven coilgun modelling was used. The tubular core (fig. 1) is suggested here with a coil inside it.